<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="container">
        <h2 class="page-header">promise封装Ajax</h2>
        <button class="btn btn-primary" id="btn">发送Ajax</button>
    </div>
    <script>
        const btn=document.querySelector('#btn');
        btn.addEventListener('click',function(){
            //创建promise
            const p =new Promise((resolve,reject)=>{
                //1.创建对象
                const xhr =new XMLHttpRequest();
                //2.初始化
                xhr.open('GET','https://api.apiopen.top/api/sentences');
                //3.发送
                xhr.send();
                //4.处理响应结果
                xhr.onreadystatechange=function(){
                    if(xhr.readyState===4){
                        //判断响应式
                        if(xhr.status>=200 && xhr.status<300){
                            //控制台输出结果
                            resolve(xhr.response)
                        }else{
                            //空状台输出响应式状态码
                            reject(xhr.status)
                        }
                    }
                }
            });
            //调用then方法
            p.then(value=>{
                console.log(value);
            },reason=>{
                console.log(reason);
            })
        })
    </script>
</body>
</html>